This application requests a shared Philips Tecnai 12 transmission electron microscope (TEM). Ultrastructural reconstruction techniques and immunogold localization methods are moving to the forefront of integrative biology. Investigators at our institution are using both approaches as part of their integrative biology studies. Their studies are limited, however, by the lack of a cryo-electron microscope (cryo-EM) at our institution. Another limitation is insufficient access to a conventional TEM. Selection of the most appropriate, basic instrument for our User Group is based on Dr. Albertine's experience as a electron microscopist in general and with Philips' TEMs in particular, Dr. Sundquist's experience with a Philips cryo-EM for reconstructions of protein assemblies, and advice from expert crystallographers in this country who use cryo-EM. Philips' TEM is selected because it simultaneously meets our needs for cryo-EM and conventional TEM. Its design provides unequaled ease of operation for both EM modes, even while the cryostage is installed. Ease of operation extends to the level of experience of investigators (from experienced to novice users), including our users who have physical disabilities. Our User Group has 18 investigators who represent the Huntsman Cancer Institute (HCI). Our User Group will require 100% of the usage of the requested TEM. Needs of other investigators, including young investigators, will be met by making the instrument available continuously, including evenings and weekends. Our User Group has 33 funded Public Health Service (PHS) research grants and 21 funded non-PHS research grants that require cryo-EM and conventional TEM. We have 16 pending PHS applications and 3 pending non-PHS grant applications that propose to use both types of TEM. Dr. Albertine, the Principal Investigator, is an expert electron microscopist who will be responsible for the shared TEM. Working with him is a full-time histology/molecular biology technician; a full-time electron microscopy technician will be hired (letter of commitment included). The Internal Advisory Committee (Drs. Albertine, Sundquist, and Fitzpatrick) will set instrument use policy and resolve use conflicts. Institutional funding commitment: We have funds for the cryostage and under-the-column CCD camera systems, which have a proven track record with the Philips Tecnai 12 TEM, from a new NIH RO1 grant and matching funds from our university (letters of commitment included). Coincident with this grant applicant is our move into the new HCI research building (spring of 1999). About 3,000 square feet of space is being designed for microscopy. This new space will accommodate the requested TEM. Furthermore, the HCI is committed to hire a full-time EM technician who will operate the requested TEM and train user users (letter of commitment included). Service contract funds are committed by the HCI (letter included) for maintaining the TEM, beginning year 02 (the year is covered by the manufacturer's warranty). The requested TEM will significantly enhance the research of our User Group, the HCI, and the Health Sciences Center community by providing, for the first time on our campus, cryo-EM.